package common.util.mail;

import java.util.Random;

public class randcode {
	   /**
	   * 产生随机字符串
	   * */
	private static Random randGen = null;
	private static char[] numbersAndLetters = null;

	public static final String randomString(int length) {
	         if (length < 1) {
	             return null;
	         }
	         if (randGen == null) {
	                randGen = new Random();
	                numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz" +
	                   "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
	                  //numbersAndLetters = ("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
	                 }
	         char [] randBuffer = new char[length];
	         for (int i=0; i<randBuffer.length; i++) {
	             randBuffer[i] = numbersAndLetters[randGen.nextInt(71)];
	          //randBuffer[i] = numbersAndLetters[randGen.nextInt(35)];
	         }
	         return new String(randBuffer);
	}
	
	//调用此方法randomString(int),int是字符串的长度，即可产生指定长度的随机字符串。
}
